Shell and tube steam generator - for sodium-cooled reactor with gas-insulated feedwater tubes

摘要

In a steam generator, particularly for a sodium-coated fast breeder reactor, of the known type comprising (i) a series of tubes installed in a vessel, each consisting of a down pipe section and an upwardly directed tubular flow section (ii) a down pipe zone and an upward tubular flow zone respectively installed in the vessel and containing groups of down pipe sections and groups of upwardly directed tubular flow sections respectively (iii) a circumscribing element is additionally provided between the down pipe and upflow pipe zone, provides a cover on an upper part of the down pipe zone, in which a thermally insulating gas layer is formed and is fixed to the vessel. advantages are reduction of thermal stresses by improvement in the insulation with an orderly arrangement of the pipes permitting easier fabrication and installation of theses.